The electrochemical stability of the boron anion receptor, tris(pentafluorophenyl) borane (TPFPB), on a carbonaceous mesocarbon microbeads (MCMB) electrode and its compatibility with the passivated solid electrolyte interphase (SEI) layer on the carbon anode were investigated. Comparison of the irreversible capacity loss of the MCMB electrode during initial galvanostatic cycling using electrolyte with and without the TPFPB additive indicates excellent electrochemical stability of TPFPB on the carbonaceous electrode. Cyclic voltammetry studies show that the SEI layer on the surface of the carbon electrode can be formed through the decomposition of ethylene carbonate in the presence of TPFPB. Prolonged cycling test verifies the long-term stability of the SEI layer on carbon in the presence of the TPFPB additive. The SEI layer is not dissolved by TPFPB even after heat-treatment under conditions which dissolve LiF salt. This suggested a cross-linked structure for the SEI layer on carbon electrode. A Li-ion cell using an electrolyte containing TPFPB displays better cycling performance than a cell without TPFPB under the same conditions. (C) 2003 The Electrochemical Society.